Seem to have made a breakthrough with signature...

Seem to have made a breakthrough with signature correctness. Most of
the remaining troubles were due to inherited members and their foreign
identifiers, but I think I found a simple way to make everyone happy.
Closes #4238, review by moors.

5 files changed, 82 insertions, 10 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/Erasure.scala b/src/compiler/scala/tools/nsc/transform/Erasure.scala
index 015481b97a..a04f1d972c 100644
--- a/src/compiler/scala/tools/nsc/transform/Erasure.scala
+++ b/src/compiler/scala/tools/nsc/transform/Erasure.scala
@@ -190,8 +190,8 @@ abstract class Erasure extends AddInterfaces
             if (!parents.isEmpty) traverse(parents.head)
           case ClassInfoType(parents, _, _) =>
             parents foreach traverse
-	  case AnnotatedType(_, atp, _) =>
-	    traverse(atp)
+          case AnnotatedType(_, atp, _) =>
+            traverse(atp)
           case _ =>
             mapOver(tp)
         }
@@ -204,9 +204,11 @@ abstract class Erasure extends AddInterfaces
   // only refer to type params that will actually make it into the sig, this excludes:
   // * higher-order type parameters (aka !sym.owner.isTypeParameterOrSkolem)
   // * parameters of methods
-  private def isTypeParameterInSig(sym: Symbol) = (
+  // * type members not visible in the enclosing template
+  private def isTypeParameterInSig(sym: Symbol, nestedIn: Symbol) = (
+    !sym.owner.isTypeParameterOrSkolem &&
     sym.isTypeParameterOrSkolem &&
-    !sym.owner.isTypeParameterOrSkolem
+    (sym isNestedIn nestedIn)
   )
   // Ensure every '.' in the generated signature immediately follows
   // a close angle bracket '>'.  Any which do not are replaced with '$'.
@@ -221,6 +223,8 @@ abstract class Erasure extends AddInterfaces
       case ch                 => last = ch ; ch
     }
   }
+  // for debugging signatures: traces logic given system property
+  private val traceSig = util.Tracer(sys.props contains "scalac.sigs.trace")
 
   /** The Java signature of type 'info', for symbol sym. The symbol is used to give the right return
    *  type for constructors.
@@ -238,7 +242,7 @@ abstract class Erasure extends AddInterfaces
       case tp                      => tp :: Nil
     }) map squashBoxed
 
-    def jsig2(toplevel: Boolean, tparams: List[Symbol], tp0: Type): String = {
+    def jsig2(toplevel: Boolean, tparams: List[Symbol], tp0: Type): String = traceSig("jsig2", toplevel, tparams, tp0) {
       val tp = tp0.dealias
       tp match {
         case st: SubType =>
@@ -270,7 +274,7 @@ abstract class Erasure extends AddInterfaces
             if (unboundedGenericArrayLevel(tp) == 1) jsig(ObjectClass.tpe)
             else ARRAY_TAG.toString+(args map jsig).mkString
           }
-          else if (isTypeParameterInSig(sym))
+          else if (isTypeParameterInSig(sym, sym0.enclClass))
             TVAR_TAG.toString+sym.name+";"
           else if (sym == AnyClass || sym == AnyValClass || sym == SingletonClass)
             jsig(ObjectClass.tpe)
@@ -334,11 +338,13 @@ abstract class Erasure extends AddInterfaces
           else jsig(etp)
       }
     }
-    if (needsJavaSig(info)) {
-      try Some(jsig2(true, Nil, info))
-      catch { case ex: UnknownSig => None }
+    traceSig("javaSig", sym0, info) {
+      if (needsJavaSig(info)) {
+        try Some(jsig2(true, Nil, info))
+        catch { case ex: UnknownSig => None }
+      }
+      else None
     }
-    else None
   }
 
   class UnknownSig extends Exception
diff --git a/src/compiler/scala/tools/nsc/util/Tracer.scala b/src/compiler/scala/tools/nsc/util/Tracer.scala
new file mode 100644
index 0000000000..c5d3fd3753
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/util/Tracer.scala
@@ -0,0 +1,37 @@
+/* NSC -- new Scala compiler
+ * Copyright 2005-2011 LAMP/EPFL
+ * @author  Paul Phillips
+ */
+
+package scala.tools.nsc
+package util
+
+class Tracer(enabled: () => Boolean) {
+  private var indentLevel = 0
+  private def ind(s: String) = (" " * (indentLevel*2)) + s
+  private def indented[T](body: => T): T = {
+    indentLevel += 1
+    try body
+    finally indentLevel -= 1
+  }
+  private def p(s: String) = {
+    System.out.print(s)
+    System.out.flush()
+  }
+  private def pin[T](x: T): T = {
+    p(ind("" + x))
+    x
+  }
+  def apply[T](name: String, args: Any*)(body: => T): T = {
+    if (enabled()) {
+      p(ind("%s(%s) = {\n".format(name, args mkString ", ")))
+      try indented(pin(body))
+      finally println("\n" + ind("}"))
+    }
+    else body
+  }
+}
+
+object Tracer {
+  def apply(enabled: => Boolean): Tracer = new Tracer(() => enabled)
+}
diff --git a/test/files/run/bug4238/J.java b/test/files/run/bug4238/J.java
new file mode 100644
index 0000000000..948989b4e7
--- /dev/null
+++ b/test/files/run/bug4238/J.java
@@ -0,0 +1,4 @@
+class J {
+	scala.collection.mutable.HashMap<String, String> x =
+		new scala.collection.mutable.HashMap<String, String>();
+}
diff --git a/test/files/run/sigtp.check b/test/files/run/sigtp.check
new file mode 100644
index 0000000000..6b961be3d0
--- /dev/null
+++ b/test/files/run/sigtp.check
@@ -0,0 +1,7 @@
+public A Bug.key()
+public Bug<A, B> Bug.foo()
+public Bug<A, B> Bug.next()
+public void Bug.next_$eq(Bug<A, B>)
+public abstract A BugBase.key()
+public abstract E BugBase.next()
+public abstract void BugBase.next_$eq(E)
diff --git a/test/files/run/sigtp.scala b/test/files/run/sigtp.scala
new file mode 100644
index 0000000000..f0cac859f5
--- /dev/null
+++ b/test/files/run/sigtp.scala
@@ -0,0 +1,18 @@
+trait BugBase [A, E] {
+  val key: A
+  var next: E = _
+}
+
+final class Bug[A, B](val key: A) extends BugBase[A, Bug[A, B]] {
+  def foo = next
+}
+
+object Test {
+  def f(clazz: Class[_]) =
+    clazz.getDeclaredMethods.toList.map(_.toGenericString).sorted foreach println
+
+  def main(args: Array[String]): Unit = {
+    f(classOf[Bug[_, _]])
+    f(classOf[BugBase[_, _]])
+  }
+}